I was going to say something similar: move the gear into the storage area and then you don't have an issue with the rack. The way you have it now, with it angled toward the walls, you will likely get a lot of cancellation, and you will also get a lot of corner gain as well. It might be a tough sub to locate and you probably won't be able to dial in location and all until the sub is actually in the room.
Since it is a basement, I think you are already going to have bass issues as it is, and you might actually need that corner gain even with a sub like that. Bass behaves different when you are surrounded by dirt and concrete.